1. Field of the Invention
The invention in general relates to line leak test probes which are used in leak detectors which monitor liquid storage and dispensing systems for leaks and more particularly to such a probe which turns the pump in the system off when a leak occurs and a manual reset switch for resetting the probe and allowing the pump to be turned back on.
2. Description of the Prior Art
Line leak test probes have been used in the petroleum industry for many years. Such line leak test probes generally report to a central monitor which utilizes the leak information to provide warning of leaks and to shut down pumps on lines that are leaking. The probes also generally include a reset switch for resetting the probe and allowing the pump to be turned back on after the leak has been fixed, or for other purposes. Such probes have become an essential part of hydrocarbon storage and dispensing facilities since even very small leaks can result in the loss of thousands of dollars in hydrocarbons and the expenses of cleanup can be enormous. It is believed that the state of the art of such probes is described in U.S. Pat. No. 4,835,717 issued to Hilary Michel and Laurence S. Slocum, which patent is hereby incorporated by reference. This patent discloses that the reset switches give occasion to abuse the system, as by turning the pump back on when a leak is known to be present. It discloses a sophisticated timing and counting system designed to lessen such abuse. However, it has been found that even this sophisticated system can be temporarily thwarted by laying a brick, for example, on the reset switch. Such thwarting of the purpose of the probe can result in significant damage to the environment, and can lead to very complicated liability issues. Thus it would be very useful to have a line leak test probe that cannot be thwarted in this manner.